Machine tool control mechanism



IN VEN TORS flrmzkwe rker A 7 TOP/WE) Dec. 12, 1950 J B ARMITAGE ETAL MACHINE TOOL CONTROL MECHANISM Filed Feb. 27, 1947 s Sheets-Sheet 1 da rqq J array It. 3% W 10 1Q Dec. 12, 1950 J. B. ARMITAGE ETAL 3, 5

7 MACHINE TOOL CONTROL MECHANISM Filed Feb. 27. 1947 5 Sheets-Sheet 2 INVENTORS 6/0427; .5. Jfrzw'zaye 017? A fink?" W mm ATTORNEY" Dec. 12, 1950 J. B. ARMITAGE ETAL 2,533,753

MACHINE TOOL CONTROL MECHANISM Filed Feb. 27, 1947 5 Sheets-Sheet 3 INVENTORS M MW ATTORNEY Dec. 12, 1950 J. B. ARMITAGE ETAL 2,533,753

MACHINE TOOL CONTROL MECHANISM Filed Feb. 27, 1947 5 sneets sheet 4 /5 I k W "W MW Dec. 12, 1950 J. B. ARMITAGE EI'AL 2,533,753

MACHINE TOOL CONTROL MECHANISM Filed Feb. 27, 1947 '5 Sheets-Sheet 5 j /za /37 68 v mwszvroxs da mv J fiwalaye, Orr/r1 W Z9 I .A TTOZNEY Patented Dec. 12, 1950 UNITED STATES PATENT OFFICE 2,533,753 MACHINE TOOL CONTROL MECHANISM Application February 27, 1947, Serial No. 731,308

12 Claims. 1

This invention relates, generally, to machine tools and more particularly to improved control mechanism for the power actuated elements of a machine tool. A general object of the invention is to provide improved controlling arrangements for the actuating mechanism of a machine tool.

Another object of the invention is to provide an improved machine tool control system especially adapted for effecting automatic operation of a milling machine of the knee and column type.

Another object is to provide an improved control system for a knee type milling machine wherein automatic trip mechanism is carried by the movable table supporting saddle and functions to actuate mechanism in the knee of the machine.

Another object is to provide an improved control system for operating a rapid traverse clutch in a machine tool in conjunction with a feed synchronizing clutch.

Another object is to provide an improved con-.

trol system for a rapid traverse drive mechanism in the knee of a milling machine, including a control lever mounted on ,the knee, as wellas manual and automatic remote control mechanism mounted on the relatively movable saddle of the machine.

Another object is to provide an improved hy draulic rapid traverse clutch actuating mechanism for a machine tool.

Another object is to provide a milling machine having movable knee, saddle and table elements with hydraulic control mechanism carried by one of the elements and operative to control the movement of any of the movable elements.

A further object of the invention is to provide a movable machine tool element with hydraulic control means to control the movement of a second movable element selectively at either one of two rates accordin to a predetermined operating cycle.

According to this invention, there is provided an improved control system for a machine tool especially adapted for milling machines of the knee and column type, whereby fully automatic operation of the machine table in continuous cycle may be effected. To this end, the rapid traverse mechanism in the knee may be controlled hydraulically by actuating a lever on the knee or may be remotely controlled from the machine saddle in coordination with automatic or manual control of the table movements. The control apparatus on the saddle includes hydraulically actuated table reversing mechanism operated by trip mechanism which simultaneously effects hydraulic control of the rapid traverse drive in the knee through an interconnecting flexible conduit. A hand lever on the saddle is arranged for manual reversal of the table and selection of feed or rapid traverse rate, a hydraulic interlock being arranged to prevent the lever from engaging the rapid traverse drive while the table control is in neutral position. A feed synchronizing clutch is provided for quickly reducing the rate of table movement when the rapid traverse drive is disconnected and is hydraulically interlocked to prevent engagement of. both the rapid traverse clutch and synchronizing clutch simultaneously.

The foregoing and other objects of this invention, which will become more fully apparent from the following detailed description, may be achieved by the particular illustrative machine tool depicted in and described in connection with the accompanying drawings, in which:

Figure 1 is a view in perspective of a milling machine of the knee and column type incorporating the novel features of the present invention;

Fig. 2 is an enlarged view in right side elevation of the machine shown in Fig. 1, the upper part of the column and other parts having been broken away;

Fig. .3 is a diagrammatic view of the work feed ing and rapid traverse transmission mechanism incorporated in the machine;

Fig. a is an enlarged view, partly in vertical section through the saddle, or the hydraulic control mechanism shown in elevation in Fig. 2; and

Figs 5 is a schematic circuit diagram. of the hydraulic control mechanism incorporated in the machine.

Although the particular machine tool shown in the drawings as exemplifying a preferred embodiment of the invention, is a milling machine of the knee and column type, it is to be understood that various features of the invention may be utilized with advantage in other machine tools of diiiier: entconstruction.

Referring more specifically to the drawings and particularly to Fig. 1 thereof, the milling machine there shown comprises essentially an integrally formed base and hollow upright column structure If! that constitutes a supporting frame carrying the cooperating tool supporting and work supporting elements of the machine. The column i8 carries at its upper forwardly projecting end a vertically movable head H in which is rotatably mounted a vertically disposed spindle l2 constituting the tool supporting element of the machine.

The complementary work supporting element of the machine is movably mounted beneath the vertical spindle I2 for supporting workpieces I3 in cooperative relationship with a milling cutter [4 carried by the spindle. The work supporting element includes the usual knee structure [5 which is slidably mounted for vertical movement along the forward face It of the column Iii. The knee l5 carries on its upper surface a saddle ll that is slidably mounted thereon for horizontal movement toward or from the column it. lhe saddle ll, in turn, carries on its upper surface a work supporting table 18 that is slidably mounted thereon for longitudinal reciprocating movement parallel with the column face it. The arrangement of the superimposed sliding work supporting elements is such that a workpiece mounted on the table i8 may be moved along any of three mutually transverse paths in positioning it relative to a cutter in the spndle l2.

Power for rotating the cutter spindle l2 and for effecting power driven movements of the superimposed Work supporting elements, is derived from a motor 283 mounted in the base of the hollow column ill, as best shown in Fig. 2. The motor 2% drives a main pulley 2i rotatably mounted on the side of the column In by means of multiple belts 22, the drive being enclosed by a hinged door. From the driving pulley 2 i, power is transmitted to rotate the spindle 52 by means of suitable speed selecting transmission mechanism within the column, such as that shown in Patent No. 2,182,421, issued December 5, 1939, to Joseph B. Armitage.

The pulley 2l is selectively connected with the ,spindle driving transmission mechanism by means of the usual friction clutch 23. Power for effecting feeding movements of the work supporting structure is derived from the spindle driving transmission through gearing 26 connected to operate a vertically disposed splined feed shaft at the right side of the column Hi, the arrangement being such that the shaft 25 is driven when and only when the clutch 23 is engaged to drive the spindle transmission. Since it is desirable to provide for movement of the work supporting elements at rapid traverse rate when the spindle is not being driven, a second splined shaft 26, disposed parallel with the shaft 25, is operatively connected by gearing 27 to be driven directly from the belt pulley 25 for effect-.

ing rapid traverse movements regardless of whether or not the clutch 23 is engaged.

The vertically disposed splined shafts 25 and 26 have sliding engagement with a spur pinion 28 and a bevel pinion 29, respectively, that are rotatably mounted in the rearwardly'projecting end of a bracket secured on the right side of the knee IS, the arrangement being such that vertical movement of the knee it may occur without interferring with the driving connections to the bracket. The spur pinion 28 on the ver-= tical feed shaft 25 is connected through spur and bevel gearing 3| to drive a horizontally disposed feed shaft 32 in the bracket 38 while the bevel pinion 22 on the vertical rapid traverse shaft 28 cooperates with a bevel gear 33 on a adjusting mechanism being more fully described in the previously mentioned Patent No. 2,182,421. From the rate changing mechanism 3i, power is transmitted at the selected feed rate through an overrunning clutch and torque limiting coupling unit 39 and a shaft it to a disconnecting and reversing mechanism i I.

The mechanism ll includes oppositely rotating clutch gears 32 and 43 arranged to be engaged selectively by a sliding clutch collar M through operation of a selector lever t5 on the front of the knee IE, to effect actuation of aknee elevating screw 36 in direction to move the knee up or down as desired, at the selected feed rate. A second pair of oppositely rotating clutch gears 1 and 49, may be engaged selectively by a clutch collar 52 actuated by a selecting lever ti on the front of the knee to effect rotation of a saddle operating screw 52 for moving the saddle IT toward or from the column id as desired, at the selected feed rate.

Power for operating the table i8 is transmitted from the feed rate shaft lli, through the gears of the reversing and disconnecting mechanism It I, to a gear 5 which meshes with the clutch gear t9 and issecured to a splined shaft 55 disposed longitudinally of the knee id. The splined shaft 55 has sliding engagement with a bevel gear 56 that is rotatably mounted in the saddle ii, and that meshes with a complementary gear 57 on a vertically disposed stub shaft 58. At its upper end, the shaft 58 carries a bevel gear 55;, which meshes with and drives oppositely rotating bevel clutch gears BI and 62, rotatably mounted in the saddle concentric with a lead screw 63, journalled at its ends in the respective ends of the table [8.

The reversing bevel clutch gears ti and 62 are rotatably mounted concentric with the table lead screw 63 and are disposed to be engaged selectively'by an intermediate slideable clutch spool or collar 6 that is splined to the lead screw and operates to turn it in either direction selectively, the screw having threaded engagement with a nut (not shown) fixed in the saddle l! in well known manner, whereby the table [8 may be caused to execute a movement in either direction selectively, at the selected feed rate.

The horizontal rapid traverse driving shaft 35 in the bracket 30 is connected by means of a hydraulically actuated clutch G5 and gearing 66 with the reversing and disconnecting mechanism if in the knee l5, the arrangement being such that when the rapid traverse clutch 65 is engaged, the reversing clutch gears for actuating the knee, saddle and table will all be operated at rapid traverse rate, the overrunning clutch unit 32 serving to permit rapid traverse operation without interference by or influence upon the rate changing mechanism 31.

In order that the table It may be caused to perform a predetermined series of movements statements in either direction at feed oif rand traverse rate in efi-e'cting eats-mane machinin ar wqrkpieses,means are provided in accordance with this invention for shifting the clutch spool F4 hydraulically in coordination with remote cone tr'ol "'o e hydraulic-rapid traverseclutch 65 and other functions in predetermined sequences. The eiutehs om 64 may aiso bejshifted by direct action of tripdogs on the table 18 'or by opera- 'tior of "a manually actuated control lever 6 1 on warrant or the saddle I l.

M nna control of the hydraulically actuated rapid traverse "clutch "(id is effected by'means'of a rapid traverse lever won th right sideofthe knee [5", that is foriiiected to operate a hydraulic pid amass valve H, the arrangement being that "when are lever!!! is lifted upward, the 'va e "'H admits "pressure to engage the rabid "ers'e clutch fiiftlrrerebypausirig 'rapid traverse move ent of the Work fsu'pporti'ng table H3 in summarise wtih the conditions of engagement "of the various; reversing and disconnecting clutches. As Ire-st "shown the enema diagram, Fig, 5, by aulic pressurero eaectmg operation of the rapid'trjaiversemldtch E "and performing the other eiihtrolfunctionsof the machine, i "derived from a urnp 73 mountedinthe knee i5 and continuously driven'by the rapid traverse shaft 34, as shown 'injFig. 3. The pumpG'S draws fluid from mine "it in the bottom of the knee through a f'coituit 75 ans discharges it under pressure thi g' h a cdiidui' t5 and past 'a pressure limitirrg "relief vai've fl'l "to a port 78 "of the rapid traverse valve H, Excess "fluid overi'iowin'g through thereliffvaive 11 enters a conduit 19 -i'eanin'gmrne "lubricating system in the knee 1 5.

When the'i'apidtralvrselever is is moved to its iipper"position', 'itmove'sawalve plunger 80 in the 'jvalve'Ti to the "left, as seen in Fig. 5, thereby establishing communication from the pressure to t Tu cen'nected with the pressur conduit is Ivepdrt 8i whichconnec'ts with apa'ssage 1ngto the 'leftenu of a sequence valve 83. "sure "in "the leftend "or "thesediierl'ce valve the notes fair :ifectiii'g rapid traverse drive.

Whenthelever T0 'is re'leasetL'it moves downward by'gravity rturiiiiigthe valve plunger 80' to the 1p ition shod/11in Fig.5, thereby cutting ()fi the simply bf pfsufe thrbilgh the port 8! iidthe left enu or'me 'seciuencevalve 83. 'A spring 88 at the right end of the valve then moves the plunger 8 thereoftothe right, thereby as-to the an, thereby placing the port as in foiiiihdnicatlon with a port e1 which is opened to the" atmosphere and'fserves to exhaust the fluid 'fiis'siiie from the rapid traverse clutch E5, gwhe'reupon aspring 89 the clutch'moves it to idisehgag'edposition.

With the valve'plun'gerstfl and 86 in the feed "panties, "(as shown the drawing, the pressure port 18 of therapidtraverse valve H has commandamu "with 4 a port 96 that connects with a fporttl of the Sequence valve 83. The port a! ifis then in communication with a port 922 from which a sonata 93 leads to a pressure actuated retarding or synchronizing hatches associated withfthe overrunning clutch unit Through "operation of the s'eduencevalve 83, as just derib the synchronizing clutch B4 is engaged I tely after the lrapid traverse clutch :65 is hzsefiga' ed ana servestsrevard'movement or the iii) 6 work supporting --'structure quickly from rapid traverse rate to the selected feed rate, thereby preventing overrunning and possible damage through unexpected continued coasting of the support after the rapid traverse clutch is disengaged. Since it is necessarythat the synchronizing clutch 9 be disengaged before the rapid traverse clutch is engagedwhen the rapid tra'verse lever 10 is lifted the sequence valve-813 operates immediately to closethe pressure port 9! before admitting pressure through the port to the rapid traverse clutch and then establishes communication between 'theport 92 leading to thesynchronizing clutch and an exhaust port 95, thereby permitting the clutch 94 to be movedto disengaged position under the action of a spring 96.

76 leading from the pump 73, is in communication with a port H20 'connected With'a conduit Hi! in the valve body H on the knee '15. From the conduit WI a flexible pressure conduit NZ-leads to a valve body E03 onfthe relatively movable saddle ii. A second fiexibleconduit "i0 4 constitutes'a return line from the valve box WE-on the saddle to the rapid traverse valve i! for effecting coordinated automatic remote control of the rapid traverse drive, as previously mentioned.

Referring more particularly 'to "the sectional view of thetable contr'ollingmechanism shown in 'Fig. 4, the arrangement for effecting automatic clutch shifting fork'ltfi that engages a groove in the clutchspool 6'4 and'is slidably mounted for movement in the saddle indirection parallel 'ito the lead screwed. Rack teeth ii]? on the shifter fork we engage the teeth of a spur gear segment 93 on one end of a control shaft iii-9, the other end of which carries a bevel gearsegment Hi The bevel segment lid meshes with a cor nlementary bevel segment III on a vertically disposed rotataloly "mounted tripping sleeve H2.

'The upper end of the trippingsleevei 52 projects above the saddle forengagement'by a trip dog H3 on the table it in well known manner, whereby the clutch spool 64 may be moved to disconnecting position upon the table arriving at a predetermined position,- as determined by the set ting of the cooperating trip dog.

Since operation of the trip-dog on'the sleeve 4 !2 cannot cause reengagement of the clutchspooi '64 with one of the reversing clutch gears, as'is required for effecting reversal in the direction (if table movement, auxiliary power means, incldd inga hydraulically actuated piston is ar ranged to effect the necessary further movement for automatic reversal. As shown, the piston" 5 55 "presents a'transverse slot H E which engages'a application of fluid pressure" to the one or the otherend of theipiston'l l5.

"Aspreviouslymentioned,"muting-of the re versing clutch spool 64 may also be effected by movement of the hand lever 51, the lever being pivotally mounted on the projecting end of a rotatable sleeve I20. The inner end of the sleeve I carries a bevel gear segment IZI which meshes with a complementary segment I22 on the tripping sleeve I I2, the arrangement being such that when the lever 61 is swung from its vertical neutral position to the right, the tripping sleeve I52 will be turned in direction to effect engagement of the clutch spool fi l in manner to effect movement of the table to the right. Similarly, movement of the lever 61 to the left engages the clutch to effect movement of the table to the left. A

spring'pressed detent mechanism I24 functions .to retain the tripping sleeve H2 in anyone of its three operating positions.

The hand lever 61 furthermore operates to effect movement of the table ill at rapid traverse rate selectively. For this purpose, the lever is mounted on the sleeve I20 by a pivot pin 225 in such manner that it may be tilted toward the table for feed rate operation or away from the table for rapid traverse rate operation. As shown,

the lower end of the lever 51 engages a sliding control rod I 26 within the sleeve E25, which is engaged at its inner end with one arm of a bell crank I21. Another arm of the bell crank I21 engages a tripping post I23 that is slidably mounted within the tripping sleeve II 2 for vertical movement. A spring pressed detent mechanism I29 engages another arm of the bell crank I21 in manner to retain the post 528 in either its upper or its lower position. At its lower end,

the tripping post I28 carries a rapid traverse valve piston I30 that cooperates with a rapid traverse valve body or cylinder I3I. The upper end of the tripping post I28 projects above the sleeve I if in position to be engaged by trip dogs on the table I8, the arrangement being such that when the post is in the lower position shown in Fig. 4, the table will operate at feed rate and when the post is moved to its upper position the rapid traverse clutch 55 is engaged to effect movement at rapid traverse rate. In addition to being movable manually by the lever 51 and mechanically by direct action of trip dogs on the table, the post .I 28 may be moved upward to rapid traverse position through the application of hydraulic pressure to the lower end of the cylinder I for lifting the valve plunger 539 in effecting coordinated automatic control of the table I8.

By providing two work holding fixtures I34 and I35 in spaced relationship on the table 58, as shown in Fig. 1, the machine may be caused to operate in manner to machine successive worl-zpieces I3 automatically in a continuous cycle through operation. of the control system functioning in accordance with this invention. That is, the workpiece It in one of the fixtures may be fed past the cutter I4, while the other fixture is being loaded by the machine operator. At the end of the cutting stroke, the direction of table movement is reversed automatically and movement in the other direction is effected at rapid traverse rate to bring the new workpiece in the other fixture into juxtaposition with the cutter. The rate of table movement is then reduced to feed rate and the second workpiece is fed past the cutter, the table being again reversed at the end of the feeding stroke. This automatic cycle may be continued indefinitely without attention from the operator beyond unloading and reloading the work holding fixtures successively.

Assuming that the work table I8 is moving from right to left at rapid traverse rate, a feed dog I31 on the table will engage the tripping post I28, moving it downward to feed position as the fixture I35 approaches the cutter I4. Further movement of the workpiece I3 relative to the cutter I4 will then occur at feed rate through the cutting stroke, whereupon a reversing dog I38 on the table will engage a reversing trip plunger I35 at the right of the tripping post I28 for effecting automatic reversal in the direction of table movement. A similar reversing plunger I49 is positioned at the left of the tripping post for effecting automatic reversal when the table is operating in the other direction.

As shown in the circuit diagram Fig. 5, when the tripping plunger I39 is engaged and depressed by the reversing dog I38, it operates through a bell crank I42 to open a poppet valve M3 that admits pressure fluid from a pressure conduit I44 that is connected with the flexible pressure conduit I32 leading from the knee to the saddle. Pressure fluid admitted through the poppet valve It?) ilows through a conduit I45 into the right end of a reversing valve housing 5%, causing a reversing valve plunger'l41 therein to be moved to the left. As the plunger I41 moves to the left, a groove I45 therein comes into register with a pressure port I49 in the housing that is connected by a conduit I directly with the pressure conduit I44, From the groove I48, pressure fluid flows longitudinally through a passageway I5I in the valve plunger to the right end of the valve i 35, thereby exerting additional force to move the valve plunger I 31 to the left and to retain it in that position. With the plunger is? in the left position, communication is established from the pressure port I49 to a port I53 connecting with a passageway I54 lead: ing to, the right end of a reversing cylinder I55 in which the reversing piston H5 is slidably mounted. Pressure in the right end of the cylinder I55 moves the piston I I5 to its extreme left position, thereby turning the tripping sleeve H2 and shifting the clutch collar 64 into engagement with the opposite clutch gear for effecting rapid traverse Valve body I3I.

movement of the table in the reverse direction.

When the piston II5 moves to the left, it uncovers a port I51 in the cylinder wall which communicates through a passageway I58 to'an annular port I59 at the other end of the cylinder. From the port 559, a conduit I60 leads to a selector valve Iii! by which it is connected with a conduit I52 leading to the lower end of the Fluid pressure in the lower end of the rapid traverse valve body I3I causes the valve plunger I39 therein to move upward to rapid traverse position, as previously mentioned. With the plunger I35 in the upper position, pressure from the pressure conduit I44 flows through a branch conduit lid to a port I65, which is then in communication with a port I56 leading to a-conduit I61. The conduit I51 leads to a port I53 in the wall of the reverser cylinder I55, the port I538 being then in communication through a groove Ids in the reversing piston H5, with a port I15 in the wall that is connected to a conduit I'll; The conduit Ill connects with the flexible return conduit I64 leading to the rapid traverse valve II where it is connected to a conduit I13 that communicates with a port I14 in the rapid traverse valve casing. With the rapid traverse valve plunger 8? in the feed position shown in the drawing, the port I'M has communication with the port 8H for exerting pressure through the passageway 82 upon the left end of the sequence valve plunger 84. As previously explained, this results in moving the plunger 84 to the right, thereby closing the pressure port 9| to out off pressure to the synchronizing clutch 94, in order to disengage it.

Further movement of the piston 34 to the right uncovers the port 85 and permits flow of the pressure fluid into the conduit 85 leading to the rapid traverse clutch 55. This results in engaging the rapid traverse drive in order that movement of the table I8 in the reverse direction may occur at rapid traverse rate.

When the rapid traverse valve piston i353 is in the upper position, communication is established through the lower end of the valve body l3l, between a port ll! connected by a conduit H8 and the conduit to the right end of the reversing valve housing M5 and a port I!!! connected by a conduit m9 and a conduit Hi! to the left end of the reversing valve housing MB. This results in neutralizing the pre sures on the ends of the reversing valve 14'! and permits it to return to its central neutral position under the influence of centraliaing springs.

In the event that it is desired to effect movement of the table in reversed direction at feed rate instead of at rapid traverse rate, the selector valve I 5! may be turned by means of an actuating handle [82. through 96 to its other position. This results in connecting the pre sure conduit IE1! from the re ersing cylinder I with a conduit I83 that le ds to a port I34 in the rapid tra erse valve housing l3! above the piston I30. Pressure exerted through the port [84 acts upon the lo er face of the spring pressed val e s eeve I95. causing it to move upwa d to establ sh communication between ports I86 and I 81. These orts are connected res ectively by conduits I88 and M9 to the conduits I86 and H8 leading to the respective ends of the reversing valve casing I46, whereby to e fect neutralization of pressure on the e ds of the valve plun er M! to permit it to centralize.

As the table it approaches the end of its move-- ment from left to right, another reversing dog I92 engages the left reverse tripping plun er Md, moving it downward and operating through a bell c ank 993 to o en a popp t valve H34. T is esta lishs communica ion from the p essure conduit M6 to the conduit it! leadin to the le t end of the reversing valve housin M6, the p essure thus exerted caus ng the rever ing valve plunger Hi? to move to the right. This est lishes communication from a pressure port 395, connect d by the conduit :59 to the pre sure conduit M4, to a port 95 connected by a conduit Hi! to the left end of the rev rsing cvlinder I55; Pressure in the cylinder results in moving the reversing piston M5 to the ri ht. thereby shifting the reversing clutch spool 54 into engagement with the opposite clutch gear to provide for movement of the table in the reverse direction. Movement of the reversing piston H5 to the right, uncovers the port l thereby establishing communication through the conduit it to the selector valve Nil. As previously explained, With the valve iii! in the position shown, the conduit 3% is connected to the conduit Hi2 leading to the bottom of the rapid traverse valve casin 63!. Pressure in the bottom of the casing 53! moves the piston 33!! upward to rapid traverse position, thereby establishing the connections whereby pressure is applied to engage the rapid traverse clutch '65 for 10 movement of the table in reversed direction at rapid traverse rate.

Since it is desirable to stop the spindle I2 when the table is reversed at the completion of a cut to prevent the cutter Hi from marring the finished workpiece I3, a hydraulic connection is provided from the rapid traverse clutch actuating conduit 86 through a conduit 20!! to a pressure actuated switch 29!. The switch 20! may be electrically connected to efiect disengagement of the spindle driving clutch 23 to stop the spindle during reverse movement of the table at rapid traverse rate. Alternatively, the spindle may be stopped through direct hydraulic action,

- for instance by connecting the conduit 20!! directly with hydraulic means for disengaging the main clutch 23 in the manner described in the previously mentioned Patent No. 2,407,913. In machines or the type shown in co-pending application Serial No. 519,366, filed January 22, 1944, now Patent No. 2,497,842, issued February 14, 1950, in which the motor drivin the spindle is separate and distinct from the mo,- tor effecting movements of the Work support, the switch 20! may be electrically connected to stop the spindle driving motor through a plugging or other braking action.

As previously explained, the rapid traverse valve plunger I30 may be moved to rapid traverse position manually by tilting the lever 67 outwardly from the table [8. However, since it is not desirable that the rapid traverse clutch be held in engagement when the reversing clutches are in neutral, the port H59 in the reversing piston H5 is so arranged that it is cut oil from communication with the port I68 when the clutch spool 54 is in neutral position, thereby preventing the transmission of pressure fluid from the valve housing l3! into the flexible conduit 14 leading to the rapid traverse valve H.

From the foregoing detailed description of and explanation of the operation of the exemplifying knee and column type millin machine herein set forth as a practical embodiment of the present invention, it will be apparent that there has been provided an improved control mechanism for a machine tool and more particularly for a milling machine of the knee and column type, whereby the work supporting table of the machine may be operated automatically in a continuous cycle or various other cycles for facilitating the rapid and economical machining of workpieces.

Although the illustrative embodiment of the invention has been described in considerable detail for the purpose of disclosing a practical operative structure whereby the invention may be practiced advantageously, it is to be understood that the particular apparatus described is intended to be illustrative only and that the various novel characteristics of the invention may be incorporated in other structural forms without departing from the spirit and scope of the invention, as defined in the subjoined claims.

The principles of the invention having now been fully explained in connection with the foregoing description of the embodying apparatus, we hereby claim as our invention:

1. In a milling machine, the combination with a column, a power source associated With said column, a tool retaining spindle rotatably mounted in said column and driven from said power source, a plurality of superimposed Wo supporting members including knee, saddle and table members slidably mounted on said colmember 11 umn for movement relative to said column and to each other, a transmission carried in said knee, a feed rate power connection from said transmission with said power source, a rapid traverse power connection including a hydraulic clutch connecting said transmission with said power source, a reversing and disconnecting means for each of said members operatively connected to said transmission for selective operation of said associated member at either feed of rapid traverse rates, a hydraulic control mechanism on said knee manually operable to control the operation of either of said members at rapid traverse rate, a hydraulic control mechanism on said movable saddle member disposed to control the operation of said table member at feed or rapid traverse rates, and a plurality of flexible connectors between said control mechanisms whereby said members may move relative to each other without interfering with the source and disposed to drive said slidable members selectively at rapid traverse rate, a clutch operatively connected in said rapid traverse transmission, a dual control mechanism operative from two of said members and connected to said clutch mechanism, a manual. control actuator disposed to operate said control mechanism on one of, said members, a manual and automatic control actuator disposed to operatesaid control mechanism on another of said members and flexible interconnecting means between said control mechanisms, whereby said members may be moved relative to one another without afifecting the operation of said control mechanisms.

3. In a machine tool having relatively movable members slidably mounted for relative movement on a column, a transmission mechanism contained in one of said members, a hydraulic clutch operable when engaged to drive said transmission mechanism at a constant feed rate, a control mechanism hydraulically connected to said clutch and operable to engage said clutch, a clutch and brake mechanism in said transmission operable to override parts of said transmission when said rapid traverse clutch is engaged and operable to brake parts of said transmission during operation at feed rate when said rapid traverse clutch is disc-n gaged, and interlocking hydraulic control mechanism operative to insure the release or" said brake before said hydraulic clutch is actuated into operative engagement.

4. In a machine tool, a base, a member movably mounted on said base, power actuated apparatus connected to effect movement of said including transmission mechanism adapted to move said member at feed rate, other transmission mechanism adapted to move said member at rapid traverse rate, a hydraulic- .ally actuated friction clutch disposed to connect said rapid traverse transmission mechanism to said member selectively, a hydraulically actu ated synchronizing clutch disposed to connect said feed rate transmission mechanism to said member selectively to reduce its rate or movement from rapid traverse rate to feed rate, a hydraulic control system connected to operate said clutches, and an interlocking control valve operative selectively to efiect engagement of said rapid traverse clutch" only when said synchronizing clutch is disengaged and to effect engagement of said synchronizing clutch only when said rapid traverse clutch is disengaged, whereby said valve is arranged to prevent engagement of both said rapid traverse clutch and said synchronizing clutch simultaneously.

5. In a milling machine the combination including a column, a power source carried in said column, a transmission mechanism operatively connected to be driven by said power source, a tool splindle rotatably carried in said column and power driven from said transmission mechanism selectively at a plurality of speed rates, a plurality of superimposed relatively movable work supportin members slidably mounted" on said column, a transmission means connectibly driven from said power source and serving to slidably drive each of said members independently and selectively at any one of a plurality of feed rates, a rapid traverse drive mechanism carried by one of said movable elements and connected to said power source to selectively drive said transmission means at rapid traverse rate, a hydraulic control mechanism'carried on said member'with said rapid traverse clutch to aiiord manual control of the movement of any or said members at rapid traverse rate, a second hydraulic control mechanism carried on another of said members and operatively connected 6. In a milling machine of the knee and column type, table driving mechanism including a rapid traverse clutch mounted in the mascot the machine and a reversing clutch mounted in the relatively movable saddle of the machine, hydraulic control mechanism mounted in-said saddle and operatively connected to control said table reversing clutch, and a flexible conduit interconnecting said control mechanism on said saddle with said rapid traverse clutch in said knee for effecting coordinated control of reversing and rate changing functions. 1

7. In a milling machine, a column, a power source in said column, a plurality of superimposed relatively movable members slidably mounted on said column, transmission means for selectively driving each of said members from said power source in said column, a rapid traverse drive mechanism connecting with said transmission, a hydraulically operated clutch in said drive mechanism to selectively'connect said drive with said transmission, a hydraulic control mechanism carried on one or said'members and operably connected to operate said clutch, manual means to operate said control mechanism, a second control mechanism carriedon-another of said members, manual and automatic means to operate said second control mechanism, and flexible interconnecting means between said second control mechanism and said first mentioned control mechanism and opera- 13 tively connected to operate said clutch selectively, whereby said control mechanisms are rel" atively movable without disturbing the effec 've control of said mechanisms.

8. In a milling machine of the knee and column type, comprising a column, a knee slidably mounted on said column, a saddle slidably mounted on said knee anda table slidably mounted on said saddle, the combination with power actuating mechanism mounted in said knee including a rapid traverse driving clutch, and table reversing mechanism mounted in said saddle and operatively connected to be driven from said mechanism in said knee, of hydraulically actuated control mechanism in said saddle responsive to table movement and operative to actuate said table reversing mechanism, and flexible conduit means interconnecting said control mechanism in said saddle with said rapid traverse driving clutch in said knee for effecting control of said rapid traverse clutch in coordinated relationship with control of said table reversing mechanism.

9. In a milling machine comprising a column,

a knee slidably mounted on said column, a saddle slidably mounted on said knee, a table slidably mounted on said saddle, power driven actuating mechanism including rate selecting apparatus mounted in said knee, table actuating mechanism. including direction selecting apparatus mounted in said saddle and operatively connected to be driven by said actuating mechanism in said knee and to drive said table, hydraulically actuated control mechanism carried by said saddle and responsive to table movement, conduit means in tenconnecting said control mechanism with said direction selecting apparatus for actuating it in response to table movement, and flexible conduit means connecting said control mechanism on said saddle with said rate selecting apparatus in said knee for controlling the rate of table movement in coordination with control of its direction of movement.

10. In a hydraulic control system for a power driven machine tool having rate selecting and direction reversing mechanism, a hydraulically actuated motor operatively connected to adjust said direction reversing mechanism from a neutral position to positions adapted to effect machine movement in either direction selectively, a control valve operatively connected to control said 7 rate selecting mechanism for effecting said movement at a high rate or at a low rate upon being positioned selectively, means to retain said valve in either its high rate or its low rate position, and

an interlocking valve operated by said direction selecting motor and serving to establish an operating connection between said rate selecting valve and said rate selecting mechanism only when said direction selecting motor is in position to eifect movement in the one or the other direction,

bi) whereby positioning of said rate selecting mechanism in high rate position through operation of said valve while said direction selecting motor is in neutral position is prevented in order to 14 avoid unintentional operation of high rate driving mechanism while said reversing mechanism is in neutral position.

11. In a milling machine of the knee and column type, comprising a column, a knee slidably mounted on said column, a saddle slidably mounted on said knee, a table slidably mounted on said saddle, power driven actuating mechanism including rate selecting apparatus and a hydraulic pressure exerting pump mounted in said knee, table actuating mechanism including direction selecting apparatus mounted in said saddle and operatively connected to be driven by said actuating mechanism in said knee and connected to drive said table, hydraulically actuated control mechanism carried by said saddle said mechanism being responsive to table movement and operatively connected to actuate said direction selecting apparatus, a flexible conduit connecting said pressure exerting pump in said knee to said control mechanism on said saddle to provide hydraulic pressure for actuating it, and another flexible conduit connecting said control mechanism on said saddle with said rate selecting apparatus in said knee for effecting control of the rate of table movement in conjunction with the control of its direction of movement.

12. In a machine tool having a base and a carriage member movably mounted on said base, power actuated apparatus operatively connected to effect movement of said carriage said apparatus including transmission mechanism adapted to effect said movement at feed rate and alternatively operating transmission mechanism adapted to effect said movement at rapid traverse rate, a hydraulically actuated friction clutch selectively engageable to connect said rapid traverse transmission mechanism to operate said carriage, a hydraulically actuated synchronizing friction clutch selectively engageable to connect said feed rate transmission mechanism to said carriage for reducing its rate of movement from rapid traverse rate to feed rate, and a hydraulic control system including interlocking means operatively connected to efiect selective engagement of said rapid traverse friction clutch only when said synchronizing clutch is disengaged and to effect selective engagement of said synchronizing friction clutch only when said rapid traverse friction clutch is disengaged, whereby simultaneous engagement of said clutches is prevented.

JOSEPH B. ARMITAGE. ORRIN W. BARKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,182,421 Armitage Dec. 5, 1939 2,198,102 Armitage Apr. 23, 1940 2,215,684 Armitage Sept. 24, 1940 2,235,085 Roehm et a1 Mar. 18, 1941 

